"I've used the same criteria to assess stencils in El Castillo and La Garma caves (both in Cantabria), said archeologist Paul Pettitt of Durham University in the UK, "and I would say that my unpublished data are consistent with the notion that stencils are of the hands of adult females."
Pettitt also cautions against jumping to too many conclusions about Snow's discovery.
"It may or may not be justified to assume that these females were the individuals who created the stencils," Pettitt explained. "We should distinguish between the stenciled and the stenciler. To play devil's advocate, how could we eliminate the hypothesis that it is male/female pairs who create stencils, the male stenciling the female?"
Secondly, Pettitt points out that the hand prints do not automatically imply that all cave art was done by women. In fact there is growing evidence that hand stencils and the more figurative art in the caves were done at very different times by entirely different people.
"It's been pointed out before that when we think of 'cave artists' we unconsciously think of bearded male hunters," said Pettitt. "Snow's work admirably reveals that adult females were being immortalized on cave walls."
Snow has also attempted to apply the same techniques to ancient hand prints in North America, but without success. Those will probably require an entirely different analysis.